java.lang.Object
- org.springframework.batch.item.ItemStreamSupport
- - org.springframework.batch.item.support.AbstractItemStreamItemReader<T>
  - - org.springframework.batch.item.file.MultiResourceItemReader<T>

All Implemented Interfaces:
ItemReader<T>, ItemStream, ItemStreamReader<T>
```
public class MultiResourceItemReader<T>
extends AbstractItemStreamItemReader<T>
```
Reads items from multiple resources sequentially - resource list is given by setResources(Resource[]), the actual reading is delegated to setDelegate(ResourceAwareItemReaderItemStream). Input resources are ordered using setComparator(Comparator) to make sure resource ordering is preserved between job runs in restart scenario.
Author:
Robert Kasanicky, Lucas Ward, Mahmoud Ben Hassine

Constructor Summary
Constructors
Constructor Description
MultiResourceItemReader()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`close()`	Close the `setDelegate(ResourceAwareItemReaderItemStream)` reader and reset instance variable values.
`org.springframework.core.io.Resource`	`getCurrentResource()`	Getter for the current resource.
`void`	`open(ExecutionContext executionContext)`	Figure out which resource to start with in case of restart, open the delegate and restore delegate's position in the resource.
`T`	`read()`	Reads the next item, jumping to next resource if necessary.
`void`	`setComparator(java.util.Comparator<org.springframework.core.io.Resource> comparator)`
`void`	`setDelegate(ResourceAwareItemReaderItemStream<? extends T> delegate)`
`void`	`setResources(org.springframework.core.io.Resource[] resources)`
`void`	`setSaveState(boolean saveState)`	Set the boolean indicating whether or not state should be saved in the provided `ExecutionContext` during the `ItemStream` call to update.
`void`	`setStrict(boolean strict)`	In strict mode the reader will throw an exception on `open(org.springframework.batch.item.ExecutionContext)` if there are no resources to read.
`void`	`update(ExecutionContext executionContext)`	Store the current resource index and position in the resource.

Methods inherited from class org.springframework.batch.item.ItemStreamSupport
getExecutionContextKey, setExecutionContextName, setName

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - MultiResourceItemReader
```
public MultiResourceItemReader()
```
- Method Detail
  - setStrict
```
public void setStrict(boolean strict)
```
    In strict mode the reader will throw an exception on open(org.springframework.batch.item.ExecutionContext) if there are no resources to read.
    Parameters:
    strict - false by default
  - read
```
public T read()
       throws java.lang.Exception,
              UnexpectedInputException,
              ParseException
```
    Reads the next item, jumping to next resource if necessary.
    Returns:
    T the item to be processed or null if the data source is exhausted
    Throws:
    ParseException - if there is a problem parsing the current record (but the next one may still be valid)
    NonTransientResourceException - if there is a fatal exception in the underlying resource. After throwing this exception implementations should endeavour to return null from subsequent calls to read.
    UnexpectedInputException - if there is an uncategorised problem with the input data. Assume potentially transient, so subsequent calls to read might succeed.
    java.lang.Exception - if an there is a non-specific error.
  - close
```
public void close()
           throws ItemStreamException
```
    Close the setDelegate(ResourceAwareItemReaderItemStream) reader and reset instance variable values.
    Specified by:
    close in interface ItemStream
    Overrides:
    close in class ItemStreamSupport
    Throws:
    ItemStreamException
    See Also:
    ItemStream.close()
  - open
```
public void open(ExecutionContext executionContext)
          throws ItemStreamException
```
    Figure out which resource to start with in case of restart, open the delegate and restore delegate's position in the resource.
    Specified by:
    open in interface ItemStream
    Overrides:
    open in class ItemStreamSupport
    Parameters:
    executionContext - current step's ExecutionContext. Will be the executionContext from the last run of the step on a restart.
    Throws:
    ItemStreamException
    See Also:
    ItemStream.open(ExecutionContext)
  - update
```
public void update(ExecutionContext executionContext)
            throws ItemStreamException
```
    Store the current resource index and position in the resource.
    Specified by:
    update in interface ItemStream
    Overrides:
    update in class ItemStreamSupport
    Parameters:
    executionContext - to be updated
    Throws:
    ItemStreamException
    See Also:
    ItemStream.update(ExecutionContext)
  - setDelegate
```
public void setDelegate(ResourceAwareItemReaderItemStream<? extends T> delegate)
```
    Parameters:
    delegate - reads items from single Resource.
  - setSaveState
```
public void setSaveState(boolean saveState)
```
    Set the boolean indicating whether or not state should be saved in the provided ExecutionContext during the ItemStream call to update.
    Parameters:
    saveState - true to update ExecutionContext. False do not update ExecutionContext.
  - setComparator
```
public void setComparator(java.util.Comparator<org.springframework.core.io.Resource> comparator)
```
    Parameters:
    comparator - used to order the injected resources, by default compares Resource.getFilename() values.
  - setResources
```
public void setResources(org.springframework.core.io.Resource[] resources)
```
    Parameters:
    resources - input resources
  - getCurrentResource
```
@Nullable
public org.springframework.core.io.Resource getCurrentResource()
```
    Getter for the current resource.
    Returns:
    the current resource or null if all resources have been processed or the first resource has not been assigned yet.

Class MultiResourceItemReader<T>

Constructor Summary

Method Summary

Methods inherited from class org.springframework.batch.item.ItemStreamSupport

Methods inherited from class java.lang.Object

Constructor Detail

MultiResourceItemReader

Method Detail

setStrict

read

close

open

update

setDelegate

setSaveState

setComparator

setResources

getCurrentResource